Kyanite
Blue blades of aluminium silicate with two hardnesses in one crystal.
- Family
- Kyanite
- Formula
- Al₂SiO₅
- Mohs
- 4.5 to 7
- System
- Triclinic
Drag to turn
Science
Kyanite forms flat blue blades in schists that were buried deep. It is famous for anisotropic hardness: about 4.5 along the blade and 7 across it, so a knife scratches it one way and not the other. It is used industrially in refractories and spark plugs.
- Mineral
- Kyanite
- Formula
- Al₂SiO₅
- Crystal system
- Triclinic
- Mohs hardness
- 4.5 to 7
- Specific gravity
- 3.53 to 3.68
- Refractive index
- 1.710 to 1.730
- Lustre
- Vitreous to pearly
- Colours
- Blue, Green, Black, Orange
Composition
Al₂SiO₅. Made of Aluminium, Silicon, Oxygen, with trace Iron, Titanium responsible for colour.
Origin
- Brazil
- Nepalgem blue
- India
- Kenya
- SwitzerlandAlps
- Tanzaniaorange kyanite
Filled dots are primary sources
Rarity
Common in metamorphic rocks; transparent, evenly blue gem material from Nepal is uncommon.
- 1 Abundant
- 2 Common
- 3 Uncommon
- 4 Rare
- 5 Exceptional
Hardness
Kyanite sits at 4.5 to 7 on the Mohs scale. It will scratch glass and holds a polish in daily wear.
Energy
Associations from crystal-healing tradition, recorded here as folklore. They are not medical claims.
Chakras
- Throat
- Third Eye
Element
- Air
Zodiac
- Aries
- Taurus
- Libra
- Pisces
Planets
- Mercury
Properties
- Alignment
- Communication
- Meditation
- Balance
Lore
The name is from kyanos, deep blue. Its history is short; nineteenth-century travellers carried it as a compass needle, said to follow north when hung from a hair.
Modern practice gives it a special status: a stone said never to hold negativity and never to need cleansing, used to align the chakras.
- Two hardnesses4.5 to 5 lengthwise, 6.5 to 7 across.
- PolymorphSame formula as andalusite and sillimanite, different pressures.